it is only a 250w. but a 600w ballast BUT I have had it under a 250w enviorlight and only just put it under the hps, think it was too close and too big of a change? what say you
It looks like your about foot and half from tops should be fine for 250w. Not sure about using light that isn't right size as ballast. Seems like it is too strong for that bulb. May not make any difference.
Metal halide can get very hot, and should be at least 12" away from your plants. I'm sure that's what your problem is. the leaves should be pretty much fine, but you can prune them off when the plants gets a little bigger..